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Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2012
Drilling Rigs and Other Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year 3 months
Drilling Rigs and Other Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Other | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years

X

- Details

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X

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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